Here is a SETI Institute seminar on a lesser known way to detect and measure exoplanets: Detecting Exoplanetary Systems with Micolensing – Scott Gaudi (SETI Talks)
From the caption:
Measurements of the demographics of exoplanets over a range of planet and host star properties provide fundamental empirical constraints on theories of planet formation and evolution. Because of its unique sensitivity to low-mass, long-period, and free-floating planets, microlensing is an essential complement to our arsenal of planet detection methods.
Dr. Gaudi will review the microlensing method, and discuss results to date from ground-based microlensing surveys. Also, Dr. Gaudi will motivate a space-based microlensing survey with WFIRST-AFTA, which when combined with the results from Kepler, will yield a nearly complete picture of the demographics of planetary systems throughout the Galaxy.
The latest images (as of Sept. 11, 2015) downloaded from NASA’s New Horizons spacecraft were stitched together and rendered on a sphere to make this flyover. This animation, made with the LORRI (Long Range Reconnaissance Imager) images, begins with a low-altitude look at the informally named Norgay Montes, flies northward over the boundary between informally named Sputnik Planum and Cthulhu Regio, turns, and drifts slowly east. During the animation, the altitude of the observer rises until it is about 10 times higher to show about 80% of the hemisphere New Horizons flew closest to on July 14, 2015. Credit: NASA/JHUAPL/SwRI, Stuart Robbins
The newest high-resolution images of Pluto from NASA’s New Horizons are both dazzling and mystifying, revealing a multitude of previously unseen topographic and compositional details. The image below — showing an area near the line that separates day from night — captures a vast rippling landscape of strange, aligned linear ridges that has astonished New Horizons team members.
“It’s a unique and perplexing landscape stretching over hundreds of miles,” said William McKinnon, New Horizons Geology, Geophysics and Imaging (GGI) team deputy lead from Washington University in St. Louis. “It looks more like tree bark or dragon scales than geology. This’ll really take time to figure out; maybe it’s some combination of internal tectonic forces and ice sublimation driven by Pluto’s faint sunlight.”
The “snakeskin” image of Pluto’s surface is just one tantalizing piece of data New Horizons sent back in recent days. The spacecraft also captured the highest-resolution color view yet of Pluto, as well as detailed spectral maps and other high-resolution images.
The new “extended color” view of Pluto – taken by New Horizons’ wide-angle Ralph/Multispectral Visual Imaging Camera (MVIC) on July 14 and downlinked to Earth on Sept. 19 – shows the extraordinarily rich color palette of Pluto.
“We used MVIC’s infrared channel to extend our spectral view of Pluto,” said John Spencer, a GGI deputy lead from Southwest Research Institute (SwRI) in Boulder, Colorado. “Pluto’s surface colors were enhanced in this view to reveal subtle details in a rainbow of pale blues, yellows, oranges, and deep reds. Many landforms have their own distinct colors, telling a wonderfully complex geological and climatological story that we have only just begun to decode.”
Additionally, a high-resolution swath across Pluto taken by New Horizons’ narrow-angle Long Range Reconnaissance Imager (LORRI) on July 14, and downlinked on Sept. 20, homes in on details of Pluto’s geology. These images — the highest-resolution yet available of Pluto — reveal features that resemble dunes, the older shoreline of a shrinking glacial ice lake, and fractured, angular water ice mountains with sheer cliffs. Color details have been added using MVIC’s global map shown above.
This closer look at the smooth, bright surface of the informally named Sputnik Planum shows that it is actually pockmarked by dense patterns of pits, low ridges and scalloped terrain. Dunes of bright volatile ice particles are a possible explanation, mission scientists say, but the ices of Sputnik may be especially susceptible to sublimation and formation of such corrugated ground.
Beyond the new images, new compositional information comes from a just-obtained map of methane ice across part of Pluto’s surface that reveals striking contrasts: Sputnik Planum has abundant methane, while the region informally named Cthulhu Regio shows none, aside from a few isolated ridges and crater rims. Mountains along the west flank of Sputnik lack methane as well.
The distribution of methane across the surface is anything but simple, with higher concentrations on bright plains and crater rims, but usually none in the centers of craters or darker regions. Outside of Sputnik Planum, methane ice appears to favor brighter areas, but scientists aren’t sure if that’s because methane is more likely to condense there or that its condensation brightens those regions.
“It’s like the classic chicken-or-egg problem,” said Will Grundy, New Horizons surface composition team lead from Lowell Observatory in Flagstaff, Arizona. “We’re unsure why this is so, but the cool thing is that New Horizons has the ability to make exquisite compositional maps across the surface of Pluto, and that’ll be crucial to resolving how enigmatic Pluto works.”
“With these just-downlinked images and maps, we’ve turned a new page in the study of Pluto beginning to reveal the planet at high resolution in both color and composition,” added New Horizons Principal Investigator Alan Stern, of SwRI. “I wish Pluto’s discoverer Clyde Tombaugh had lived to see this day.”
Mars Orbiter spacecraft marks one year of its life around the red planet today. After successfully completing one year of the mission life around Mars, now a large data set has been acquired by all five payloads of MOM. On this occasion Space Applications Centre, (ISRO), Ahmedabad has brought out a Mar Atlas which contains a compilation of images acquired by Mars Colour Camera (MCC) and results obtained by other payload results in a form of scientific atlas.
The NASA/ESA Hubble Space Telescope imaged three magnificent sections of the Veil Nebula in 1997. Now, a stunning new set of images from Hubble’s Wide Field Camera 3 capture these scattered stellar remains in spectacular new detail and reveal its expansion over the last years.
Deriving its name from its delicate, draped filamentary structures, the beautiful Veil Nebula is one of the best-known supernova remnants. It formed from the violent death of a star twenty times the mass of the Sun that exploded about 8000 years ago. Located roughly 2100 light-years from Earth in the constellation of Cygnus (The Swan), this brightly coloured cloud of glowing debris spans approximately 110 light-years.
In 1997, Hubble’s Wide Field and Planetary Camera 2 (WFPC2) photographed the Veil Nebula, providing detailed views of its structure. Now, overlaying WFPC2 images with new Wide Field Camera 3 (WFC3) data provides even greater detail and allows scientists to study how far the nebula has expanded since it was photographed over 18 years ago.
Despite the nebula’s complexity and distance from us, the movement of some of its delicate structures is clearly visible — particularly the faint red hydrogen filaments. In this image, one such filament can be seen as it meanders through the middle of the brighter features that dominate the image.
Astronomers suspect that before the Veil Nebula’s source star exploded it expelled a strong stellar wind. This wind blew a large cavity into the surrounding interstellar gas. As the shock wave from the supernova expands outwards, it encounters the walls of this cavity — and forms the nebula’s distinctive structures. Bright filaments are produced as the shock wave interacts with a relatively dense cavity wall, whilst fainter structures are generated by regions nearly devoid of material. The Veil Nebula’s colourful appearance is generated by variations in the temperatures and densities of the chemical elements present.
This video begins with a ground-based view of the night sky, before zooming in on the Veil Nebula, a supernova remnant, as the NASA/ESA Hubble Space Telescope sees it. Credit: ESA/Hubble, Digitized Sky Survey, Nick Risinger (skysurvey.org), Music: Johan Monell
The blue coloured features — outlining the cavity wall — appear smooth and curved in comparison to the fluffy green and red coloured ones. This is because the gas traced by the blue filter has more recently encountered the nebula’s shock wave, thus still maintain the original shape of the shock front. These features also contain hotter gas than the red and green coloured ones [1]. The latter excited longer ago and have subsequently diffused into more chaotic structures.
Hidden amongst these bright, chaotic structures lie a few thin, sharply edged, red coloured filaments. These faint hydrogen emission features are created through a totally different mechanism than that which generates their fluffy red companions, and they provide scientists with a snapshot of the shock front. The red colour arises after gas is swept into the shock wave — which is moving at almost 1.5 million kilometres per hour! — and the hydrogen within the gas is excited by particle collisions right at the shock front itself.
This video pans over NASA/ESA Hubble Space Telescope observations of the Veil Nebula. The features of the nebula, shown in different colours, are caused by the shockwave of the dying star and the interstellar gas it was surrounded by. Credit: NASA, ESA, Hubble Heritage Team, Music: Johan Monell
Despite utilising six full Hubble fields of view, these new WFC3 images cover just a tiny fraction of the nebula’s outer limb. Located on the west side of the supernova remnant, this section of the outer shell is in a region known as NGC 6960 or — more colloquially — the Witch’s Broom Nebula.
This video shows the movement of the gas filaments within the Veil Nebula in comparing the observations made in 2015 with observations from 1997. The expansion of the gas in comparison to the background stars are clearly visible. Credit: NASA, ESA; Hubble Heritage Team. Acknowledgment: J. Hester (Arizona State University)
Notes
[1] The colours in the image have been chosen to help identifying the three different species of gas; they do not represent the real colours of the nebula.